MRP1, or Multidrug Resistance-associated Protein 1, is a member of the ATP-binding cassette (ABC) transporter family. This protein is encoded by the ABCC1 gene and is known for its role in exporting various substrates across cellular membranes. MRP1 is particularly involved in the efflux of drugs and endogenous compounds, including glutathione, leukotrienes, and bile acids.